Recently, the use of portable terminals, such as cellular phones, PDAs, and GPSs, is rapidly increasing. Most of the portable terminals include a mechanical or physical keypad as an interface between them and a human.
Such a keypad is generally configured as a combination of a plurality of alpha-numeric key buttons. Usually, alphabetic letters included in the alpha-numeric key buttons of the keypad correspond to a language of a nation where the keypad is commercialized.
In the keypad having the above described configuration, accordingly, it is very important to achieve an effective array of a predetermined number of key buttons for the sake of easy message transfer.
The recent spread of cellular phones throughout various cultures around the whole world, including English culture, Chinese culture, and other cultures, has given rise to an increased requirement with respect to
an effective keypad array and use suitable for the input of letters of various languages, more particularly, alphabetic letters of inflectional languages.
To fulfill the above mentioned increased requirement, therefore, there is a necessity to provide a new keypad array and input method thereof for achieving an improvement in input efficiency of alphabetic letters of various languages, including English, Chinese, etc., and allowing a keypad to be applicable to various portable terminals that are commercialized in various nations.